Indoor air quality impacts of an improved wood stove in Ghana and an ethanol stove in Ethiopia, IN: Energy for Sustainable Development, In Press, Corrected Proof, Available online 24 May 2009, ISSN 0973-0826, DOI: 10.1016/j.esd.2009.04.003.

This study was undertaken to assess the potential of two types of improved cookstoves to reduce indoor air pollution in African homes. An ethanol stove, the CleanCook, was tested in three locations in Ethiopia: the city of Addis Ababa and the Bonga and Kebribeyah Refugee Camps, while a wood-burning rocket stove, the Gyapa, was evaluated in Accra, Ghana.

In both countries, kitchen concentrations of PM2.5 and CO, the two pollutants responsible for the bulk of the ill-health associated with indoor smoke, were monitored in a before and after study design without controls. Baseline (`before’) measurements were made in households using a traditional stove or open fire. `After’ measurements were performed in the same households, once the improved stove had been introduced. PM2.5 was measured using UCB Particle Monitors, which have photoelectric detectors. CO was measured with Onset HOBO Loggers. In Ghana and Kebribeyah Camp, CO was also measured with Gastec diffusion tubes.

In Ghana, average 24-hour PM2.5 concentrations decreased 52% from 650 [mu]g/m3 in the ‘before’ phase to 320 [mu]g/m3 in the ‘after’ phase (p = 0.00), and average 24-hour kitchen CO concentrations decreased 40% from 12.3 ppm to 7.4 ppm (p = 0.01). Including all three subgroups in Ethiopia, average PM2.5 concentrations decreased 84% from 1 250 [mu]g/m3 to 200 [mu]g/m3 (p = 0.00) and average CO concentrations decreased 76% from 38.9 ppm to 9.2 ppm (p = 0.00). 24-hour average CO levels in households using both the Gyapa and CleanCook stoves met, or nearly met, the World Health Organization (WHO) 8-hour Air Quality Guideline. PM2.5 concentrations were well above both the WHO 24-hour Guideline and Interim Targets.

Therefore, despite the significant improvements associated with both of these stoves, further changes in stove or fuel type or household fuel mixing patterns would be required to bring PM to levels that are not considered harmful to health.

Now Kenyan designers have built a cooker that uses the trash as fuel to feed the poor, provide hot water and destroy toxic waste, as well as curbing the destruction of woodlands.

After nine years of development, the prototype “Community Cooker” is close to being rolled out in overcrowded refugee camps as well as slums around the country where the filth encourages diseases including cholera.

Invented by Nairobi architect Jim Archer, the cooker combines simplicity with the capacity to confront several environmental challenges simultaneously. The design was highly commended at the World Architecture Festival in Barcelona last year.

The prototype is working in Nairobi’s Kibera slum, said to be the biggest in Africa, where around 800,000 people live.

Potatoes, rice and tea cook on some of the eight hotplates above a roaring, spitting furnace. A joint of meat roasts in an oven that can also be used for bread.

Behind the black-painted corrugated iron cooking area, rubbish collected by local youths dries on racks before being pushed into the furnace.

Technicians have spent three years modifying the firebox to produce enough heat to destroy toxins in the rubbish, particularly plastics, although they are striving to get the temperature higher still.

The stove is one of several projects giving hope amid endemic violence, crime and disease in the huge slums. In another part of Kibera, a group of 35 youths have developed a farm on a former rubbish dump, feeding themselves and selling cucumbers, pumpkins and tomatoes.

HEALTH HAZARDS

The health hazards posed by garbage assault the eye as soon as you enter Kibera.

The slum looks as if it is literally built on trash, with waste including excrement filling the rough mud streets and streams, so only fetid pools remain.

Pigs and goats forage in the waste and children play by filthy streams and drink from water pipes covered in garbage.

Slums like Kibera, home to 60 percent of Nairobi’s population, receive no garbage collection or other services from city authorities.

Many inhabitants struggle to afford the kerosene for their own stoves, so Archer’s idea was to clear at least some of the waste, while providing hot water for bathing and communal cooking facilities.

While the prototype cooker, in Kibera’s Laini Saba village, has been dogged by local squabbles, drought and design problems, it proved the idea worked. A tall chimney carries the once-choking fumes away and initial emissions tests have been favourable, Archer’s firm says.

Now the Kenyan Red Cross is preparing to install similar cookers in the Dadaab and Kakuma refugee camps near the Somali border, where cholera has already broken out this year, and at least one European aid organisation is looking at wide deployment.

Juma Ochieng of the Red Cross told Reuters the Community Cooker had benefits for health, sanitation and conservation, and would create employment for young people working to build and maintain the stoves.

Residents of Kibera, scene of bloodshed in last year’s Kenyan election crisis and home to many criminal gangs, agree.

“It employs the youth….They would be stealing if they were not here …They would have been in trouble if we didn’t have this cooker,” said James Mokaya, 56, a member of the community that runs the prototype.

The Kibera stove cost more than $10,000 to build as a prototype but both Ndede and Mumo Musuva, an architect working for Archer’s practice, estimate each would cost $5-6,000 once produced in larger numbers. This compares with $50 million for industrial incinerators in Europe.

SLOWING DEFORESTATION

The Red Cross’s Ochieng says the cookers will also reduce the risk of deadly slum fires from kerosene stoves in densely populated slums.

“As the Red Cross we are looking at taking them countrywide very soon,” he said. He thinks 8-10 will be built by the end of this year and at least a 100 over the next five years, depending on donor funding.

Henry Ndede, of the Kenya regional office for the United Nations Environment Programme (UNEP), which provided funds to set up the Kibera cooker, says more work needs to be done to improve materials used in it and raise the temperature still higher to ensure the destruction of carcinogens in plastic.

The stove reaches around 650 Celsius (1,200 Fahrenheit) at present. Ndede says 1,000 degrees is needed but is happy that the prototype has proven rubbish can be turned into energy.

“It is an ideal item for densely populated areas like slums and refugee camps,” he said. “Every city in this country has a slum area with highly combustible material with high calorific value.”

He said the cooker would also relieve serious pressure on forest areas. The Dadaab camp houses 250,000 people although it was built for 80,000. Surrounding woodland has been cut down to provide cooking fuel.

“In Dadaab you have to go more than 50 km (30 miles) to fetch firewood. It takes you two weeks on donkey-back,” he said. (Additional reporting by Ruth Njeng’ere; Editing by Sara Ledwith)